Wednesday, June 27, 2012

Nano-Size Germ Killers

Tiny knives could be important weapons against superbugs

Drug-resistant tuberculosis is roaring through Europe, according to the World Health Organization. Treatment options are few—antibiotics do not work on these highly evolved strains—and about 50 percent of people who contract the disease will die from it. The grim situation mirrors the fight against other drug-resistant diseases such as MRSA, a staph infection that claims 19,000 lives in the U.S. every year. Hope comes in the form of a nanotech knife. Scientists working at IBM Research– Almaden have designed a nanoparticle capable of utterly destroying bacterial cells by piercing their membranes.

The nanoparticles’ shells have a positive charge, which binds them to negatively charged bacterial membranes. “The particle comes in, attaches, and turns itself inside out and drills into the membrane,” says Jim Hedrick, an IBM materials scientist working on the project with collaborators at Singapore’s Institute of Bioengineering and Nanotechnology. Without anintact membrane, the bacterium shrivels away like a punctured balloon. The nanoparticles are harmless to humans—they do not touch red blood cells, for instance—because human cell membranes do not have the same electrical charge that bacterial membranes do. After the nanostructures have done their job, enzymes break them down, and the body flushes them out.

Hedrick hopes to see human trials of the nanoparticles in the next few years. If the approach holds up, doctors could squirt nanoparticle-infused gels and lotions onto hospital patients’ skin, warding off MRSA infections. Or workers could inject the particles into the bloodstream to halt systemic drug-resistant organisms, such as streptococci, which can cause sepsis and death. Even if it succeeds, such a treatment would have to overcome any unease over the idea of nanotech drills in the bloodstream. But the nastiest bacteria on the planet won’t succumb easily.

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In its broadest sense, science (from the Latin scientia, meaning "knowledge") refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research.

Fields of science are commonly classified along two major lines: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being experimented for its validity by other researchers working under the same conditions.